Betaflight 4.5 firmware released: What’s new?

While everyone was busy unwrapping Christmas gifts, the BetaFlight team released a new upgrade for its popular open-source flight controller firmware. In this article, we will focus on what’s new in Betaflight 4.5 and if it’s worth upgrading from previous BF versions with the risk of undetected bugs of a new release.

The BF 4.5 is an incremental release, meaning that basic flight parameters have not changed from the previous version (4.4), although iTerm is slightly better-suppressed. Previous filters, PID settings, and other tuning values should not need to change. This version requires BetaFlight Configurator 10.10; the latest version can be downloaded here.

Upgrade recomandation

A full Chip erase is mandatory when flashing. Re-configuring from scratch is safer than importing a CLI dump or a saved Preset. Users of GPS Rescue, Angle, and Horizon modes should NOT use their old values. Otherwise, most flight, Rx, Mode, OSD, and GPS parameters have not changed since 4.4. Any new or re-named parameters will get default values, so importing a 4.4 save file (Presets>Save) is, in most cases, OK.

What’s improved in Betaflight 4.5?

The GPS rescue mode was first introduced in BF 4.3 and is now in the V4.5 it is chiseled and improved. The CPU cost and task timing for GPS data have been extensively reviewed and optimized. Even so, GPS Rescue puts a huge load on a CPU. It is best to use a 4k PID loop on most processors, especially at 57600 baud for reliability. Improved support has bee added for UBlox GPS modules, particularly M9 and M10, improving rescue reliability and smoothness.

Due to major improvements in IMU heading determination code, flyaways are now much less likely due to heading errors. Now, rescues can be initiated closer to home without disarming the motors. Immediate disarm on rescue initiation close to home will now only occur when the quad is within a 5-meter radius of home and below a less-than-landing altitude.

In v4.5, if Mag is properly oriented, configured, and calibrated and is confirmed to return reliable heading information, the quad should rotate correctly at the start of a rescue and point directly to home every time, regardless of drift. This significantly improves the safety of a rescue on windy days.

BetaFlight V4.5 brings a colorful HD OSD. White, green, orange, or red colors can now be used for text, and symbols are now supported for compatible HD Vtx modules, eg, Walksnail. More color customization has also been added to the LED strip. Additional color range and frequency settings were enabled for the Rainbow LED Strip effect. It can be used now at the same time as the Larsson effect.

Improved Angle and Horizon modes

In BF 4.5, the Angle and Horizon flight modes differ entirely from the previous firmware version. Angle mode is a lot snappier due to the angle_feedforward parameter. High-angle P values, which used to cause oscillation, are no longer needed. The responsiveness to stick inputs is much quicker at P values that do not oscillate. It also now uses the user’s RC Rate settings to determine stick feel, facilitating the transition to Acro or Horizon. Angle no longer has its own specific stick configuration.

Horizon mode has been changed a lot. Horizon mode provides self-leveling when the sticks are centered, and the quad is close to being flat but flies like acro at higher stick angles or when the quad is steeply angled. When the sticks are in the center region, and the quad is nearly flat, the self-leveling strength can be as strong or gentle as the pilot likes. The frame angle at which there is no self-leveling can also be adjusted. With the default settings, flips and rolls to be performed, and with a bit of tweaking, inverted hangs are possible.

EzLanding for smoother landing

This is a newly developed feature (available CLI only), that makes landings less bouncy, even when Air mode is on. This is achieved by restricting the amount to which airmode can increase throttle, and by attenuating iTerm, when the throttle is low and sticks are centered. To enable this new feature, go set mixer_type = EZLANDING in CLI.

Blackbox and logging updates

Blackbox now supports 8 channels of data per debug. Not all debugs have been updated to take advantage of this, but it is extremely helpful when developing.

All eight Debug values also can be shown graphically and named correctly in Configurator’s Sensors Tab.

Several new debugs have been added, and their display in Blackbox should be correct.
Blackbox GPS Map display and GPX export to enable external GPS mapping.

Want to know more?

Enjoy FPV University‘s video explaining the advantages of the new BF 4.5 firmware even more.